I need a little help in determining how our
astronaunts could see clear enough to perform
all the complex evolutions shown in all the
video and photo's of the 6 successful lunar
missions. We all know that the solar energy available at the Moon and at the Earth is
about 1350 watts/meter-squared and that the
luminance available is about 128,770 lumens/
meter-squared. We know that human visibility
becomes extremely difficult at 10,000 lumens/
meter-squared due to glare and completely
impossible at about 12,000 lumens/meter-squared. Also, we know that our 6000 mile deep atmosphere cuts the available luminance
down to a little more that 10,000 lumens/meter-squared on the brightest high noon day on earth and cuts the 1350 watts of
available energy down to about 350 watts/meter-squared. So, a brightness that is 13 times greater on the moon is so intense that the astronaunt would need visor shielding that is as dark as or darker than welding goggles. If any one has every worn even low value welding shades he knows that you can't see very much of anything unless you are looking directly at the welding arc.
With their visors down and on the bright side of the moon the astronaunts can see well enough to perform all of their evolutions and even perform the difficult task of striking a golf ball. Does any one have any info on the value of the shading required to shield out 120,000 lux of the available 128,770, or even half that amount
in case your argument is that they were at all times in the twilight zone.

I got most of my info and figures from:

http://techreports.larc.nasa.gov/ltrs/ltrs.html

You can also get this info from the refrence
section of your local library.

<font size=-1>[ This Message was edited by: BOO on 2002-11-24 12:04 ]</font>

Maybe that's why they had the visors. Duh!!!

Two comments:

- All of the Apollo lunar surface activities took place close to lunar dawn or dusk so that the astronauts did not have to deal with the full "noontime" solar intensity but only a fraction of it.

- Estimates of the depth of the atmosphere vary depending on how you consider it, but I don't know of anyone who pegs it at 6000 miles (most satellites orbit below that!). For purposes of blocking solar radiation, the relevant figure is probably more like 50, if not less.

Well that does not answer my question.
I got my figures from NASA sites. If you ar
considering shieding from solar radiation you
have to consider all levels of the atmosphere
and 6000 miles is what is listed albiet there
may only be a few ions at this distance. If you look at a lunar phase calendar you will
notice that we had almost a full moon for Apollo 12 and it landed close to the center of that visible region. What level of shading is required in the visors and just how much can you see through that shading when you are looking away from the sun?

Could you please read my post again and try to answer some of the questions? Maybe you
know of a few physical properties to show that the visors are not just toys.

I have a hard time believing that the earth's atmosphere cuts down the incoming light by a factor of 13. If that were the case, wouldn't earth's surface be nearly impossible to see from orbit? Where are you getting these numbers from?

The Earth's atmosphere attenuates the incoming solar radiation by 30% on a clear day and of course more during cloudy days.

For example, we received approximately 640 W/m2 (peak) today in Houston.

I'm not going to even attempt to tackle BOO's claim that welding goggle type shielding would be necessary. He states it as if it were obvious, but does not show any calculation to demonstrate why...he does do a good job of setting us up with enough raw data that he might fool the layman into believing his conclusion without further calculation, but given the vast body of evidence that NASA is *not* lying to us about Apollo I'm more tempted to think that BOO's handwaving is somehow flawed. Someone with a more complete knowledge of this topic should go into detail to prove this however.

Here is an interesting quote from the Apollo 12 Technical Debriefing I found on the ALSJ website, pages 10-11 and 10-12. It never ceases to amaze me just how much is contained in the ALSJ...every single mundane detail about the missions seems to be in there...and yet if Apollo was hoaxed it must all be made up.

Here can be found a picture of an astronaut with his visor up. http://www.hq.nasa.gov/office/pao/Hi...-146-22296.jpg

This is a description of the photo from http://www.hq.nasa.gov/office/pao/Hi...es17.html#Hass
I'm not sure what implications, if any, this has. It doesn't seem safe to me to lift your visor while in sunlight on the moon's surface for obvious reasons. However, I don't have all the facts either, so if someone could explain a little further on this topic it would be appreciated.

Edit: By "unsafe" I am thinking more along the lines of radiation and/or UV rays rather than "brightness" BTW

<font size=-1>[ This Message was edited by: cigarette_repairman on 2002-11-24 03:35 ]</font>

I don't see any reason to believe that the surface was too bright. The proof is in the photography. The astronauts took hundreds of photos of the lunar surface without having to resort to any special filters or the like. It doesn't seem to be any more difficult to handle the glare there than it would be to handle it on a bright snow-field here on Earth. Just put on some dark goggles or the equivilent.

I suppose you want actual numbers though. I guess that's fair. Unfortunately, I can't provide them. I personally doubt the numbers as provided in the OP myself. Either they are wrong, or they are overlooking some element that makes them irrelevant to the situation discussed. The latter is more likely in my opinion.

However, it is a fact that all the Apollo landings happened within a day or so of lunar dawn. None of them had to deal with the full lunar noon. The highest Sun would have been at the end of the 3 day missions. The Sun rises about 12&deg; a day on the Moon, so at worst it would be about 36-48&deg; above the horizon.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

<a name="2-11-24.MoS"> page 2-11-24.MoS aka Moo S
On 2002-11-23 21:43, BOO wrote: To? Moo N in June
well? boo? count me in IN spiret if not in fact
I'll attempt the "SQUARE" meter tail
and avoid A LUM n debait for the nonce 4:00 A.M.
ok the finger I came up with was shadow = 11:1 for 11
so maybe there some shade to crawl into?
about 1350 watts/meter-squared
WHAT CAME TO MY MIND was the Bones in the hand tail
remember WHEN i lifted my arm?
well I had done that excersize B4
with the welding glass but I saw the Bones in My hand
(BWUW) so dont leave out that GORE
that must be X-Ray vision line if you ask me
to about 350 watts/meter-squared.
so on the moon why are there no reports of this?
I mean X-rays should have been up there should they NOT
have been? ? I see no report at all about the BONES in the hand Gore

<font size=-1>[ This Message was edited by: HUb' on 2002-11-24 07:04 ]</font>

<a name="2-11-24.MoM"> page 2-11-24.MoM aka Moo M
On 2002-11-24 03:18, David Hall wrote: tO 2
MAYBE I CAN CHIME IN WITH A NUMBER/
http://www.badastronomy.com/phpBB/vi...263&forum=3&18
I suppose you want actual numbers though. I guess that's fair.
4:16 A.M. t_0 had past and the Shanti had sail out of
the lagoon.. word had past to Jetson the 9"
So I grabed the AN/UPN1 and headed up to the open hatch
on the MAIN deck .. being carefull to put the Gamma shield over the apature
and settin the 1 Alpha on highest scale I turned the On Off {it screamed Pegged the needle and died right there in my hand} looking out the hatch it was VERY bright .. I went below DeLusioned 4EVAr

<font size=-1>[ This Message was edited by: HUb' on 2002-11-24 07:48 ]</font>

The earth's atmosphere may be 6,000 miles deep according to some definitions and estimates, but only some of that will be optically significant. The lower five or six miles contains most of the goop that will attenuate in the visible spectrum. The atmosphere varies in density.

The Hubble Space Telescope orbits at altitudes far lower than 6,000 miles, and so do the ISS and the space shuttle. The atmosphere at that point has no measurable optical effect, so what you see from that position in orbit will be fundamentally identical to what you see from the moon. If the atmosphere attenuated the light from the sun by a factor of 13, space photography would be radically different than it is now.

As for the visor, I've looked through an Apollo LEVA. The attenuation is approximately what you would get from dark, mirrored sunglasses. The LEVA in question is in storage right now, so I can't take readings with a light meter.

BOO, you stated those numbers as if "we all know" them, but in fact we don't. At least I sure don't. I think a good starting place might be for you to give us sources/cites for your information, so we can all catch up to you. It doesn't do me any good to try to explain numbers that I don't know where they come from. You said you got them all from NASA, it should not be hard to provide them to us. Then we can begin to address the questions you have from a point of knowledge.

Apollo 12 took place from November 14-24, 1969, landing on November 19. Full moon was November 23rd. First quarter was November 16, and the landing site was 23 degrees west, so dawn at the landing site would have been after that by over a day.

__________________
Everything I need to know I learned through Googling.

I am not sure what you are trying to
say in this paragraph. We all know that all of the lunar landings were made in daylight
precisely so that the astronaunts could see
the surface clear enough to make any corrections in attitude to avoid falling into
a hole or smashing into a boulder. So I can't
find any info that would lead me to believe that they landed before dawn or in the dark,
dusk or dawn.

[quote]
On 2002-11-24 11:37, Irishman wrote:
BOO, you stated those numbers as if "we all know" them, but in fact we don't. At least I sure don't. I think a good starting place might be for you to give us sources/cites for your information

The best thing for you to do since you obviously cannot answer my question is to go
to the books and learn enough to answer my
questions instead of dismiss them with impertinence.

Am I to understand that you would have me
believe that all we need on the moon to
shield our eyes from the intense radiation
encountered in an athmosphereless void so
close to our sun is a cool pair of raybans.
I am sorry, but that is harder for me to
swallow than the Flat Earth theory.

[quote]
On 2002-11-24 12:23, BOO wrote:
BOO - with all due respect, it is you who need to provide cites and references for your calculations/assumptions for the relative strength of sunlight on the moon as compared to Earth. You have given us absolutely no reason to believe you know what you are talking about.

It has been discussed here at length that the lunar landings happened just after local sunrise, I cannot find a source for the information at the moment but others will point you in the right direction. However, unless you provide information on how you arrived at your illumination numbers, this is nothing more than a side issue.

[arrg - spelling even after installing a spell checker!]

<font size=-1>[ This Message was edited by: SpacedOut on 2002-11-24 12:58 ]</font>

[quote]
On 2002-11-24 12:23, BOO wrote:
No! No!! No!!!

It is you who have made the assertion. It is your responsibility to provide the citation(s) to back them up.

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

[quote]
On 2002-11-23 22:14, ToSeek wrote:
Two comments:

- All of the Apollo lunar surface activities took place close to lunar dawn or dusk so that the astronauts did not have to deal with the full "noontime" solar intensity but only a fraction of it.

IN physics as taught to me in the seventies
I learned that on earth dusk and dawn are
possible because we have an atmosphere. The
radiation reaching us is further attenuated
by the encreased lenght of travel through the
atmosphere at a low angle of incidence. If we
apply this same physics to the moon then
there can be no true dusk or dawn on the
Lunar landscape since there is now atmosphere
to increase the shielding at low angles of
incidence. It then follows that the distance
delta from noon to dusk or dawn has no effect in attenuating the affects of solar
radiation on the astronaunts or their equipment. On the moon you are either in full
sun or total darkness. As a matter of fact
if the sun is striking your entire body at
a low angle of incidence you are being exposed to more radiation than if it were
striking just your head shoulders and backpack during high angles of incidence. So,
if the sun is hitting you and you are casting a shadow you are in full sun, all
1350 watts/meter-squared or 128,770 lumens/
meter squared. My question in this post is
how long does it take for lunar terrain to heat up from minimum night temperatures to maximum daylight temperatures.

[quote]
On 2002-11-24 02:54, cigarette_repairman wrote:
Here can be found a picture of an astronaut with his visor up. http://www.hq.nasa.gov/office/pao/Hi...-146-22296.jpg

This is a description of the photo from http://www.hq.nasa.gov/office/pao/Hi...es17.html#Hass
I'm not sure what implications, if any, this has. It doesn't seem safe to me to lift your visor while in sunlight on the moon's surface for obvious reasons. However, I don't have all the facts either, so if someone could explain a little further on this topic it would be appreciated.

Edit: By "unsafe" I am thinking more along the lines of radiation and/or UV rays rather than "brightness" BTW

<font size=-1>[ This Message was edited by: cigarette_repairman on 2002-11-24 03:35 ]</font>

IN physics as taught to me in the seventies
I learned that on earth dusk and dawn are
possible because we have an atmosphere. The
radiation reaching us is further attenuated
by the encreased lenght of travel through the
atmosphere at a low angle of incidence. If we
apply this same physics to the moon then
there can be no true dusk or dawn on the
Lunar landscape since there is now atmosphere
to increase the shielding at low angles of
incidence. It then follows that the distance
delta from noon to dusk or dawn has no effect in attenuating the affects of solar
radiation on the astronaunts or their equipment. On the moon you are either in full
sun or total darkness. As a matter of fact
if the sun is striking your entire body at
a low angle of incidence you are being exposed to more radiation than if it were
striking just your head shoulders and backpack during high angles of incidence. So,
if the sun is hitting you and you are casting a shadow you are in full sun, all
1350 watts/meter-squared or 128,770 lumens/
meter squared. My question in this post is
how long does it take for lunar terrain to heat up from minimum night temperatures to maximum daylight temperatures.

Ummm...not sure why BOO is quoting my question and then quoting his own previous post directly after it

<font size=-1>[ This Message was edited by: cigarette_repairman on 2002-11-24 15:13 ]</font>

BOO check out the albedo of the moon and the earth. The average albedo of the earth is about 30%, the moon is ony 7%.

The earths albedo at worst during the day is about 20% and during the night is 5%. So only at night we are a little bit off from the moon.

Check out theese resopective moon and earth fact sheets:
http://nssdc.gsfc.nasa.gov/planetary.../moonfact.html
http://nssdc.gsfc.nasa.gov/planetary...earthfact.html

To make it easier on you here are quotes form the sites:


[emphasis mine]

So you would be blinded more from the earth than if you were on the moon unportected. of course if you are on the moon don't look directly at the sun. It would have the same effects as if yu looked directly at the sun on the earth, retina damage and blindness. But i doubt that the astronaughts looked directly at the sun for that length of time.

IF you don't believe that the earth is brighter, go out on a snowy day and look at the snow. If the sun is out it is blindingly bright. Not imagine only 7% of that reflecting back at you.
See:
http://www.windows.ucar.edu/tour/lin...th/albedo.html
http://www.aas.org/publications/baas...spd2000/20.htm

P.S. if i am misunderstanding albedo please inform me. But from what i have gotten from my geography classes that is what it means.

_________________
"I am not conceited, i'm perfect"
"It takes Thousands to fight a battle for a mile, Millions to hold an election for a nation, but it only takes One to change the world." by Dan Sandler 2002

<font size=-1>[ This Message was edited by: g99 on 2002-11-24 16:00 ]</font>

You claimed that they landed when the Moon was nearly full. You're wrong. What else are you wrong about? If you make any further claims, I'd appreciate your providing sources. I apologize for not doing likewise in my previous post, but I was in rather a rush. Here they are now:

Moon phases in 1969

Apollo 12 timeline

__________________
Everything I need to know I learned through Googling.

Meanwhile, according to this graph, the attenuation of visible light by the atmosphere (the difference between the dark blue line and the light blue line) is almost nonexistent.

__________________
Everything I need to know I learned through Googling.

The difference between sunlight on the Moon and on the Earth is so slight as to be negligible.

So, BOO is wrong in his claim that sunlight on the Moon is 13 orders of magnitude brighter than on Earth!

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

BOO, wouldn't this also imply that since the Shuttle and ISS are above the earths's atmosphere, it would be impossible for astronauts to perform EVAs?

So, BOO is wrong in his claim that sunlight on the Moon is 13 orders of magnitude brighter than on Earth!

To be fair on BOO, he claimed that the sun was merely 13 times brighter, not 13 orders of magnitude.

If we take the recorded exposure time/f-stop combinations from the lunar photography at face value, the amount of light falling on the moon is very similar to what we find here on earth.